Since the bones of an infant are suppler, the infant should be held by an adult or supported on a highchair to keep safely. However, long-term holding will produce the fatigue of the adult. Although the highchair can support the weight of the infant, the height of the highchair needs to be adjusted frequently to correspond to the growing up of the infant. Further, when dining out, it is very troublesome to bring the highchair out otherwise it is necessary to request a height-fixed highchair from the restaurant. Therefore, there is an increasing desire for an infant highchair capable of adjusting the height thereof easily and bringing out conveniently.
FIG. 1 shows a conventional infant highchair. In general, the leg frame is configured to form an inverted-V shape or L shape. The height-adjusting means is a locking slot. During the height adjustment, a user needs to press buttons (not shown) on both sides of the height-adjusting means 120 so as to move a sleeve 100 up and down along the leg tubes 110 whereby achieving the height adjustment of the infant highchair. However, the height adjustment would be more laborious due to the total weight of the infant pulse the highchair itself. Further, conventional highchairs also have a drawback that they cannot be detached and folded into a minimum volume due to the restriction of the leg frame so that it is very inconvenient in storage and conveyance.